Question

Give the formula for the acidic oxide of (a) \(\mathrm{HNO}_{3}\) (b) \(\mathrm{HNO}_{2}\) (c) \(\mathrm{H}_{2} \mathrm{SO}_{4}\)

Short answer

Answer: The formulas for the acidic oxides of the given compounds are as follows: - HNO₃: NO₂ - HNO₂: NO₂ - H₂SO₄: SO₃

Step-by-step solution

Identify the non-metal ion in the given compound

In each given compound, we need to find the non-metal ion to be combined with oxygen to form the acidic oxide. (a) In HNO₃, the non-metal ion is N (nitrogen). (b) In HNO₂, the non-metal ion is also N (nitrogen). (c) In H₂SO₄, the non-metal ion is S (sulfur).

Combine the non-metal with oxygen to form acidic oxide

Now that we have identified the non-metal ions, we will combine them with oxygen to form the acidic oxides. (a) For HNO₃ with nitrogen (N), we form nitrogen oxide (NOx). There are several oxidation states of nitrogen oxide possible, but the most common acidic oxide is nitrogen dioxide (NO₂). The formula for the acidic oxide of HNO₃ is NO₂. (b) For HNO₂ with nitrogen (N), just like in the first case, the most common acidic oxide is nitrogen dioxide (NO₂). The formula for the acidic oxide of HNO₂ is NO₂. (c) For H₂SO₄ with sulfur (S), we form sulfur oxide (SOx). There are two common oxidation states for sulfur oxides: sulfur dioxide (SO₂) and sulfur trioxide (SO₃). However, sulfur trioxide SO₃ is the most common acidic oxide. The formula for the acidic oxide of H₂SO₄ is SO₃.

Key concepts

Chemical Formula

When we talk about a chemical formula, it refers to a way of representing the elements in a compound and the relative number of atoms of each involved element. Formulas are the shorthand of chemistry, enabling scientists to quickly convey information about chemical substances.

For instance, determining the chemical formula for acidic oxides involves identifying the central non-metal ion from a compound and combining it with oxygen. In our exercise, we looked at compounds like HNO₃, HNO₂, and H₂SO₄. The chemical formulas derived from these acids are NO₂ and SO₃ for the acidic oxides of nitrogen and sulfur, respectively. These formulas indicate that nitrogen dioxide comprises one nitrogen atom and two oxygen atoms, while sulfur trioxide includes one sulfur atom bonded to three oxygen atoms.

Oxidation States

The oxidation state, or oxidation number, is a concept in chemistry that allows us to assign a value to an element in a compound that represents its loss or gain of electrons. Essentially, it's a bookkeeping tool that helps us understand how electrons are distributed among atoms in a molecule.

Non-metal ions can have several oxidation states, which can lead to different acidic oxides. For example, nitrogen can exhibit a range of oxidation states from -3 to +5. The common acidic oxide of nitrogen - nitrogen dioxide (NO₂) - has nitrogen in the +4 oxidation state. Similarly, the sulfur in sulfur trioxide (SO₃) has an oxidation state of +6. Recognizing and understanding these oxidation states are crucial when figuring out the corresponding acidic oxide formula from a given acid.

Non-Metal Ions

Non-metal ions are typically found in acids and contribute significantly to the properties of the compounds they form, including the acidic oxides. An ion is an atom or molecule that has gained or lost one or more electrons, giving it a net electrical charge.

In the case of acidic oxides, we are examining compounds formed when these non-metal ions bond with oxygen. A non-metal ion like nitrogen in HNO₃ and HNO₂ is responsible for the acidic properties of the oxides NO₂ or N₂O₄ (dinitrogen tetroxide, which is a dimer of NO₂). For acids like H₂SO₄, the non-metal ion sulfur leads to the formation of the acidic oxide SO₃. Recognizing the non-metal ion in the parent acid is a vitally important step in predicting the formula of the acidic oxide.